This invention relates to mixtures of disperse dyes, compositions comprising dispersions of such mixtures and processes for the colouration of synthetic materials with such mixtures. More particularly, the invention relates to mixtures of the dyes of the so-called pyrroline type with those of the so-called anthraquinone type.
Dyes of the pyrroline type are disclosed, for example, in U.S. Pat. No. 3,013,013, U.S. Pat. No. 3,013,018, GB-A-2191498, EP-A-0327077, EP-A-0511625 and WO-A-94010248.
In particular, WO-A-94010248 discloses dyes of the pyrroline type having the formula (1) 
wherein:
D is a group of Formula (2): 
or a group of Formula (3): 
or a group of Formula (4): 
R1 is alkyl, cycloalkyl, aryl, alkenyl or aralkyl each of which may be optionally substituted;
R2 is optionally substituted C7-20-alkyl; or
R1 and R2 together with the nitrogen atom to which they are attached form a pyrrolidino or piperidino ring;
R3 is alkyl, alkenyl or aralkyl each of which may be optionally substituted, xe2x80x94SO2alkyl, xe2x80x94SO2aryl, or xe2x80x94COR in which R is xe2x80x94H or alkyl, phenyl, cycloalkyl or aralkyl each of which may be optionally substituted, or xe2x80x94H; and
R4 is an electron withdrawing group;
R6 is optionally substituted C1-6-alkyl; or
R1 and R6 together with the nitrogen atom to which they are attached form a pyrrolidino or piperidino ring;
R7, R8, R9 and R10 each independently is alkyl, cycloaklyl, aryl, alkenyl or aralkyl, each of which may be optionally substituted or xe2x80x94H;
W is oxygen or sulphur;
Z is a direct link or Nxe2x80x94R11 in which R11 is xe2x80x94H or optionally substituted alkyl or aryl;
Ring A is unsubstituted apart from the xe2x80x94NR1R2 group or is substituted by from 1 to 4 further groups; and
Ring B is unsubstituted or substituted by from 1 to 3 groups; except for 3-(4-(N,N-di-n-octylamino)phenyl)-4-cyano-5-dicyano methylidene-2-oxo-2,5-dihydropyrrole provided that:
(a) when D is a group of Formula (3), R1 and R6 are different and R1 is not xe2x80x94C2H5, xe2x80x94C3H7 or xe2x80x94C4H9 when R6 is xe2x80x94C2H4phenyl, xe2x80x94C3H6phenyl and ethyl substituted by xe2x80x94OH, xe2x80x94CN, xe2x80x94OCH3, xe2x80x94OC2H4OC2H5, xe2x80x94NHCOCH3-Ophenyl and xe2x80x94NHSO2CH3; or
(b) at least one of R1 and R6 is branched chain alkyl.
Commercially available dyes of the pyrroline type are, for example, dyes of the formula: 
where RA is H (Kayalon Polyester Brilliant Blue F2B-S); or CH2CHxe2x95x90CH2 (Kayalon Polyester Blue-Green FG-S); and dyes of the formula 
where XA is C4H9 and YA is CH(CH3)C5H11.
Dyes of the anthraquinone type are also well known. For example, dyes and mixtures of dyes each within the formula given below are commercially available as C.I. Disperse Blue 60 type dyes: 
where RB is (CH2), xe2x80x94Oxe2x80x94RB1, in which n is 1-6 and RB1, is straight or branched alkyl or alkoxy (and examples of RB are C2H4OCH3, C3H6OCH3, C3H6OC2H5 and C3H6OC2H4OCH3) and ZB is O or NH.
However, if dyes of the pyrroline type alone (or mixtures of such pyrroline-type dyes) are dyed on polyester, build up to heavy depths of shade is difficult to achieve, light fastness is average at best, the dyes tend to be rather sensitive to changes in the pH of dyeing and undesirable redder shades are sometimes seen.
If dyes of the anthraquinone type alone (or mixtures of such anthraquinone-type dyes) are dyed on polyester, they often exhibit very good light fastness, but with poor build up. Moreover, they are tinctorially very weak and therefore expensive for colouring polyester. Moreover, high strength liquid or grain formulations cannot be achieved. In addition, although good build up can be achieved, the shade becomes duller as the dye builds up.
We have now found surprisingly that if certain dyes of the pyrroline type are mixed with certain dyes of the anthraquinone type, brighter shades are maintained as the dyes build up. Moreover, the dyeings have good light fastness. In particular, as compared with anthraquinone dyes alone, when using mixtures with pyrroline dyes, products of high colour strength can be readily formulated, with greater cost-effectiveness.
Thus the invention provides a dye mixture comprising
(A) at least one pyrroline type dye of the formula (I); 
wherein R1 is H, C1-20alkyl or C2-20alkenyl; and D is aryl; and
(B) at least one anthraquinone type dye of the formula (II) 
wherein RB is (CH2)nORB1;
RB1 is a straight or branched chain C1-6alkyl or C1-6alkoxy-C1-6alkyl;
n is 1-6; and
ZB is O or NH.
Component (A) preferably comprises a dye of the formula (I) wherein D is a group of the formula (a) 
wherein each of R2 and R3 independently is an alkyl, cycloalkyl, aryl, alkenyl or aralkyl group.
In the above formula (I), the alkyl group represented by any of R1-R3 is preferably a C1-20-alkyl, more preferably a C1-12-alkyl and especially a C1-8-alkyl group. The cycloalkyl group represented by R2 or R3 is preferably a C4-8-cycloalkyl and more preferably a cyclohexyl group. The aryl group represented by R2or R3 is preferably phenyl. The alkenyl group represented by any of R1-R3 is preferably a C2-10-alkenyl, more preferably a C2-6-alkenyl and especially a C2-3-alkenyl group, such as allyl. The aralkyl group represented by any of R1-R3 is preferably a phenyl-C1-6-alkyl, more preferably a phenyl-C1-3-alkyl, especially phenylethyl or 3-phenylpropyl.
The alkyl group represented by R3 is more preferably a C7-15-alkyl, still more preferably a C7-12-alkyl and especially a C7-9-alkyl group.
The alkyl group represented by R1 is more preferably a C1-6-alkyl and still more preferably C1-8-alkyl group.
R1 is especially preferably xe2x80x94H, C1-4-alkyl or C2-3alkenyl, more preferably xe2x80x94H or C1-4-alkyl and especially xe2x80x94H.
D is preferably a group of Formula (a).
The alkyl groups represented by any of R1-R3 may be straight or branched chain alkyl groups. R2 is preferably C1-12-alkyl more preferably C1-8-alkyl especially unsubstituted C1-8alkyl. R3may be C7-12-alkyl and preferably C7-9-alkyl, especially unsubstituted C7-9-alkyl or may be unsubstituted C1-6-alkyl. Where D is a group of Formula (a) it is preferred that one or both of R2 and R3 is branched, more preferably branched at an xcex1- or xcex2-, i.e. 1- or 2-, position. It is preferred that R2 and R3 are different. It is also preferred that ring A is unsubstituted apart from the NR2R3 group.
A preferred sub-group of dyes of Formula (I) is that in which D is a group of Formula (a):
R1 is alkyl or xe2x80x94H;
R2 is alkyl;
R3 is C7-20-alkyl; and
Ring A is unsubstituted apart from the xe2x80x94NR2R3 group.
Another preferred sub-group of dyes of Formula (I) is that in which D is a group of the Formula (a);
R1 is xe2x80x94H or alkyl;
R2 is unsubstituted C1-8-alkyl;
R3 is unsubstituted C1-6-alkyl; and
Ring A is unsubstituted apart from the xe2x80x94NR2R3 group; and
R2 and R3 are different or at least one of R2 and R3 is a branched chain alkyl.
An especially preferred sub-group of dyes of Formula (I) is that in which D is a group of Formula (a):
R1 is xe2x80x94H;
R2 is unsubstituted C1-8 alkyl;
R3 is unsubstituted C7-9 alkyl; and
Ring A is unsubstituted apart from the xe2x80x94NR2R3 group.
A further especially preferred sub-group of dyes of Formula (I) is that in which D is a group of Formula (a);
R1 is xe2x80x94H;
R2 is n-propyl or n-butyl;
R3 is 1-methylhexyl or 2-ethylhexyl; and
Ring A is unsubstituted apart from the xe2x80x94NR2R3 group.
Typical especially preferred components (A) in mixtures embodying the invention are:
(1) a pyrroline type dye of the formula (I), wherein R1 is H, R2 is C4H9 and R3 is 1-methyl-n-hexyl (A1) or a mixture thereof with up to 10% by weight of component (A), of a pyrroline type dye (A2) of the formula (I), wherein R1 is H and each of R2 and R3 is C4H9;
(2) a pyrroline type dye of the formula (I), wherein R1 is H, R2 is ethyl and R3 is n-octyl (A3) or 2-ethyl-n-hexyl (A4) or a mixture of dyes (A3) and (A4); and
(3) a pyrroline type dye of the formula (I), wherein R2 is C4H9, R3 is 3-phenylpropyl and R1 is H (A5) or allyl (A6) or a mixture of dyes (A5) and (A6).
When R1 is H, dyes of Formula (I) may exist in a tautomeric form represented by Formula (IA): 
wherein:
D is as hereinbefore defined.
The dyes of Formula (I) where D is a group of Formula (a) may be prepared by reaction of an aniline of Formula (III): 
in which Ring A is as hereinbefore defined, firstly with a compound of Formula R2X in which R2 is as hereinbefore defined and X is a halogen such as xe2x80x94Cl, xe2x80x94Br or xe2x80x94I or other leaving group, such as a tosylate, mesylate or alkylsulphonate in the presence of a base such as an alkali metal carbonate or alkaline earth metal carbonate such as K2CO3 or CaCO3 and secondly with a compound of formula, R3X in which R3 and X are as hereinbefore defined in the presence of a base as above to form an aromatic amine of Formula (IV); 
Alternatively the aromatic amine of the Formula (IV) may be prepared by reductive alkylation of the aniline of Formula (III) with an appropriate ketone or aldehyde. The reductive alkylation may be performed in an inert liquid medium such as an alcohol or ester optionally in the presence of an acid such as an aliphatic carboxylic acid, for example, acetic and propionic acids and aromatic sulphonic acid e.g. 4-toluenesulphonic acid using a metal or supported metal catalyst such as palladium or platinum on carbon and hydrogen, optionally at elevated temperature and pressure. Alternatively, reducing agents such as sodium borohydride may be used. After the reductive alkylation a second alkyl group may be introduced as described above.
The aromatic amine of Formula (IV) is then reacted with a 3-halopyrrole of Formula (V): 
in which R1 is as hereinbefore defined and X is preferably a halogen such as xe2x80x94Cl or xe2x80x94Br to form a compound of Formula (I). The reaction may be performed in a liquid medium such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulphoxide, sulpholane, N-methylpyrrolidone, acetonitrile, toluene or tetrahydrofuran or any mixture thereof and at a temperature from xe2x88x9220xc2x0 C. to 50xc2x0 C. The product may be isolated by any convenient means such as pouring the reaction mixture into a mixture of ice and water and recovering the precipitated product by filtration. The product may be purified by any convenient means such as trituration or recrystallisation from organic liquids particularly alkanols such as methanol, ethanol and esters such as ethylacetate or mixtures thereof.
The 3-halo-2-oxopyrrole of Formula (V) may be prepared by halogenation of a compound which may be represented by Formulae (VI), (VI1) and (VI2) 
with a halogenating agent such as phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, thionyl chloride or phosgene at a temperature of from xe2x88x9220xc2x0 C. to 50xc2x0 C. in a liquid medium such as N,N-dimethylformamide, N,N-diethylacetamide, dimethylsulphoxide, sulpholane, N-methylpyrrolidone, acetonitrile or tetrahydrofuran. The product may be used without isolation with improvement in yield in the preparation of compounds of Formula (1) described above or may be isolated by evaporating the liquid medium.
Alternatively a compound of Formula (IV) may be reacted directly with the compound represented by Formulae (VI), (VI1) or (VI2) in a liquid medium such as toluene in the presence of a halogenating agent such as phosphorus oxychloride.
The compounds represented by Formulae (VI) or (VI1) my be prepared by reaction of diethyloxalate with a compound for Formula (VII); 
in the presence of a base such as an alkali metal alkoxide preferably a sodium or potassium C1-6-alkoxide and especially sodium or potassium methoxide, ethoxide, n- or iso-propoxide, n-, iso- or tertiary-butoxide in a liquid medium, preferably an alkanol such as methanol, ethanol, n- or iso-propanol or n-, iso- or tertiary-butanol, at a temperature of from 10xc2x0 C. to 60xc2x0 C. The product may be isolated by cooling the reaction mixture and collection by filtration.
The compound of Formula (VII) may be prepared by reaction of malononitrile with a compound of Formula (VIII):
NCCH2CNxe2x80x83xe2x80x83Formula (VIII)
in the presence of a base such as sodium methoxide in a liquid medium such as methanol at a temperature of from xe2x88x9220xc2x0 C. to 60xc2x0 C. The product may be isolated by filtration.
A dye of Formula (I) in which R1 is other than xe2x80x94H may be prepared by reaction of the corresponding dye of Formula (I) in which R1 is xe2x80x94H in a liquid medium, preferably an amide such as dimethylformamide or an ether such as tetrahydrofuran or diethylether in the presence of a base, preferably an alkali metal carbonate such as potassium carbonate or an alkali metal hydride such as sodium hydride at a temperature of 0xc2x0 C. to 120xc2x0 C. with an appropriate alkylating agent. Where R1 is alkyl an appropriate alkylating agent is an alkyl halide, preferably an alkyl iodide, bromide or chloride. Where R1 is alkenyl an appropriate alkylating agent is an alkenyl halide, preferably an alkenyl bromide. These dyes may be isolated by evaporating the liquid medium or by filtration from the reaction mixture.
As previously mentioned, component (A) may be a mixture of two or more dyes of Formula (I) wherein to R3 inclusive, D and Ring A are as hereinbefore defined.
Reference is now made to component (B), which preferably comprises at least one anthraquinone type dye of the formula (II), wherein ZB is O or NH, more preferably O, n is 1, 2 or 3, more, preferably 2 or 3 and RB1 is methyl, ethyl or methoxyethyl. Thus, it is especially preferred that component (B) is an anthraquinone dye of the formula (II) wherein ZB is O and RB is C2H4OCH3, C3H6OCH3, C3H6OC2H5 or C3H6OC2H4OCH3 or a mixture of any two or more such anthraquinone type dyes, especially a mixture of any two, or all three, of the dyes (B1), (B2) and B3), each of the Formula (II) in which ZB is O,
which dye (B1) is a dye wherein RB is C3H6OCH3;
which dye (B2) is a dye wherein RB is C3H6OC2H4OCH3; and
which dye (B3) is a dye wherein RB is C3H6OC2H5.
When component (B) is a mixture of dyes (B1) and (B2), the ratio by weight of dye (B1): dye (B2) is preferably from 30:70 to 60:90 inclusive, more preferably from 45:55 to 48:52.
The dyes of the formula (II) wherein RB is hydrogen may be prepared, for example, by reaction of 2,3-dicyano-1,4-diamino-anthraquinone with sulphuric acid. This dye may then be reacted with a primary amine RBXNH2 to obtain a dye of the formula (II) wherein RBX is any of the groups of RB other than hydrogen. Alternatively, certain of such dyes of the formula (II) may be prepared from the 2,3-dicyano-1,4-diaminoanthraquinone by reaction with each of sulphuric acid and a secondary alcohol to provide a dye wherein RBX is secondary alkyl. Another method of preparing dyes of the formula (II) where RB is a group as previously defined other than hydrogen is by reaction of the corresponding 1,4-diaminoanthraquinone carboxylic anhydride with a primary amine RBXNH2 where RB1X is as defined above. Such reactions are disclosed in Ventkataraman, The Chemistry of Synthetic Dyes, Academic Press, New York and London, 1970, Vol. III, pages 413-415.
In general, in a preferred mixture of components (A) and (B), the ratio by weight, of component (A) component (B) is from 3:97 to 60:40 inclusive, more preferably from 8:92 to 40:60 inclusive, especially from 10:90 to 30:70 inclusive.
In especially preferred mixtures, of components (A) and (B), component (A) is
(1) a pyrroline type dye of the formula (I), wherein R1 is H, R2 is C4H9 and R3 is 1-methyl-n-hexyl (A1) or a mixture thereof with up to 10% by weight of component (A), of a pyrroline type dye (A2) of the formula (I), wherein R1 is H and each of R2 and R3 is C4H9; or
(2) a pyrroline type dye of the formula (I), wherein R1 is H, R2 is ethyl and R3 is n-octyl (A3) or 2-ethyl-n-hexyl (A4) or a mixture of dyes (A3) and (A4); or
(3) a pyrroline type dye of the formula (I), wherein R2 is C4H9, R3 is 3-phenylpropyl and R1 is H (A5) or allyl (A6) or a mixture of dyes (A5) and (A6); and
component (B) is a mixture of anthraquinone-type dyes (B1) and (B2), each of the formula (II), which dye (B1) is a dye wherein ZB is O and RB is C3H6OCH3 and which dye (B2) is a dye wherein ZB is O and RB is C3H6OCH2CH2OCH3, wherein the ratio, by weight, of the dye (B1): dye (B2) is preferably from 45:55 to 48:52.
At least for a mixture of component A(1), with component (B), the ratio, by weight, of component A(1) component (B) is preferably from 5:90 to 30:70 inclusive.
A mixture embodying the invention of at least one dye of formula (I) (component A) and at least one dye of the formula (II) (component B) may additionally comprise at least one other dye (component C), especially a yellow, orange, red or brown dye capable of producing a navy or black shade.
Mixtures embodying the invention can be prepared by a number of methods including
Typically, the dyes are dissolved in a hot solvent, for example, by placing the dyes in a suitable solvent and heating up to the reflux temperature of the solvent until the dyes are dissolved, thereafter filtering to provide a solution, and then allowing the solution to cool and crystals to form. The resultant mixture may then undergo further processing, such as milling and spray drying. Examples of suitable solvents for this process are organic solvents such as aromatic hydrocarbons, chlorinated hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, alcohols, amides, sulphoxides, esters, ketones and ethers. Specific examples of organic solvents are toluene, ethyl cellosolve, acetone, chlorobenzene, pyridine, dimethyl formamide, diemthylsulphoxide, ethyl acetate, benzene, tetrahydrofuran and cyclohexane.
(a) The dyes are mixed and then milled together to give an intimate blend which is then spray dried to give a solid mixture; or
(b) each dye is milled separately and then mixed in the required ratio before spray drying.
Each dye is spray dried separately and then mixed in the required ratio by a dry blending process.
The mixtures give especially bright shades which are maintained as the dyes build up. Dyeings with the mixtures have good light fastness. The mixtures have high colour strength and can be readily and cost-effectively formulated.
Mixtures embodying the invention provide especially useful disperse dyes valuable for colouring synthetic textile materials and fiber blends thereof by exhaust dyeing, padding or printing, and may be formed into dispersions for this purpose. They may also be used in, for example, ink jet printing of textiles and non-textiles, dye diffusion, thermal transfer printing and in the colouration of plastics.
According to other aspects, the invention provides a composition comprising at least the dye mixture and a dispersing agent, surfactant or wetting agent, suitable for providing such a dispersion and also a process for colouring a synthetic textile material or fibre blend thereof which comprises applying to the synthetic textile material or fibre blend a mixture comprising at least one dye of the formula (I) and at least one dye of the formula (II).
The synthetic textile material may be selected from aromatic polyester, especially polyethylene terephthalate, polyamide, especially polyhexamethylene adipamide, secondary cellulose acetate, cellulose triacetate, and natural textile materials, especially cellulosic materials and wool. An especially preferred textile material is an aromatic polyester or fibre blend thereof with fibres of any of the above mentioned textile materials. Especially preferred fibre blends include those of polyester-cellulose, such as polyester-cotton, and polyester-wool. The textile materials or blends thereof may be in the form of filaments, loose fibres, yarn or woven or knitted fabrics.
The mixtures of dyes of formulae [I] and [II] optionally in conjunction with other disperse dyes may be applied to the synthetic textile materials or fibre blends by processes which are conventionally employed in applying disperse dyes to such materials and fibre blends.
Suitable process conditions may be selected from the following
(i) exhaust dyeing at a pH of from 4 to 6.5, at a temperature of from 125xc2x0 C. to 140xc2x0 C. for from 10 to 120 minutes and under a pressure of from 1 to 2 bar, a sequestrant optionally being added;
(ii) continuous dyeing at a pH of from 4 to 6.5, at a temperature of from 190xc2x0 C. to 225xc2x0 C. for from 15 seconds to 5 minutes, a migration inhibitor optionally being added;
(iii) direct printing at a pH of from 4 to 6.5, at a temperature of from 160xc2x0 C. to 185xc2x0 C. for from 4 to 15 minutes for high temperature steaming, or at a temperature of from 190xc2x0 C. to 225xc2x0 C. for from 15 seconds to 5 minutes for bake fixation with dry heat or at a temperature of from 120xc2x0 C. to 140xc2x0 C. and 1 to 2 bar for from 10 to 45 minutes for pressure steaming, wetting agents and thickeners (such as alginates) of from 5 to 100% by weight of the dye optionally being added;
(iv) discharge printing (by padding the dye on to the textile material, drying and overprinting) at a pH of from 4 to 6.5, migration inhibitors and thickeners optionally being added;
(v) carrier dyeing at a pH of from 4 to 6.5, at a temperature of from 95xc2x0 C. to 100xc2x0 C. using a carrier such as methylnaphthalene, diphenylamine or 2-phenylphenol, sequestrants optionally being added; and
(vi) atmospheric dyeing of acetate, triacetate and nylon at a pH of from 4 to 6.5, at a temperature of 85xc2x0 C. for acetate or at a temperature of 90xc2x0 C. for triacetate and nylon for from 15 to 90 minutes, sequestrants optionally being added.
In all the above processes, the dye mixture may be applied as a dispersion comprising from 0.001% to 6, preferably from 0.005 to 4%, of the dye mixture in an aqueous medium.
A particular aspect of the invention provides a composition comprising a mixture of dyes (I) and (II), optionally at least one other disperse dye and, additionally, optionally at least one further ingredient conventionally used in colouring applications such as a dispersing agent, surfactant or wetting agent. The composition typically comprises from 1% to 65%, preferably 10 to 60%, more preferably 20 to 55%, of the total dye mixture in a liquid, preferably an aqueous, or solid medium. Liquid compositions are preferably adjusted to pH 2 to 7, more preferably pH 4 to 6.
Typical examples of dispersing agent are lignosulphonates, naphthalene sulphonic acid/formaldehyde condensates and phenol/cresol/sulphanilic acid/formaldehyde condensates, typical examples of wetting agent are alkyl aryl ethoxylates which may be sulphonated or phosphated and typical examples of other ingredients which may be present are inorganic salts, de-foamers such as mineral oil or nonanol, organic liquids and buffers. Dispersing agents may be present at from 10% to 200% on the weight of the dye mixtures. Wetting agents may be used at from 0% to 20% on the weight of the dye mixtures.
The compositions may be prepared by bead milling the dye mixture with glass beads or sand in an aqueous medium. The compositions may have further additions of dispersing agents, fillers and other surfacants and may be dried, by a technique such as spray drying, to give a solid composition comprising from 5% to 65% of dyestuff.
In addition to the above-mentioned application processes, the dye mixtures may be applied to synthetic textile materials and fibre blends by ink-jet printing, the substrates optionally having been pre-treated to aid printing. For ink-jet applications, the application medium may comprise water and a water-soluble organic solvent, preferably in a weight ratio of 1:99 to 99:1, more preferably 1:95 to 50:50 and especially in the range 10:90 to 40:60. The water-soluble organic solvent preferably comprises a C1-C4-alkanol, especially methanol or ethanol, a ketone, especially acetone or methyl ethyl ketone, 2-pyrrolidone or N-methylpyrrolidone, a glycol, especially ethylene glycol, propylene glycol, trimethylene glycol, butane-2,3-diol, thiodiglycol or diethylene glycol, a glycol ether, especially ethylene glycol monomethyl ether, propylene glycol monomethyl ether or diethylene glycol monomethyl ether, urea, a sulphone, especially bis-(2-hydroxyethyl) sulphone or mixtures thereof.
The dye mixtures may also be applied to textile materials using supercritical carbon dioxide, in which case the dye formulating agents may optionally be omitted.